I have a small HVAC unit in my apartment, and recently it began making a constant annoying clicking sound. Since maintenance did not show for 2 days, I opened up the panel and realized that the sound was coming from the actuator. In my attempt to stop the sound, I unplugged a wire that seemed to be associated with the actuator. No luck, but after reconnecting that wire to its terminal, the unit will not engage into cooling mode. It seems like the condenser is not turning on, since I can't distinguish any new noise between fan only mode and cooling mode.

I opened up the electrical panel thinking maybe I had blown a fuse or something, and the control circuit board has a flashing D13 light. Any idea what this means?

Also, there are a few buttons on the circuit - TEST/RESET, LAST ERROR, and COMM SETUP. I'm not sure if I should press them or not.